/*#pragma GCC target ("avx2")
#pragma GCC optimize ("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")/**/
#include<bits/stdc++.h>
/**/
//typedef int ll;
typedef long long ll;
typedef unsigned long long ull;
typedef std::string str;
//typedef vector<std::vector<ll>> vv;
/*typedef __int128 vll;
typedef unsigned __int128 uvll;*/
#define llll std::pair<ll , ll>
#define pb push_back
#define pf push_front
#define halo cout << "hello\n"
#define fi first
#define sec second
#define vv(x) std::vector<std::vector<x>>
#define all(a) a.begin() , a.end()
const ll limit = 1e9+7;
const ll ous = 5e5 + 7;
const ll dx[4] = {-1 , 0 , 1 , 0} , dy[4] = {0,1,0,-1};
template <typename T> std::string type_name();
ll n , m;std::vector<ll> ar;
std::vector<ll> adj[ous] , lc(ous) , v;
ll cnt = 0;
ll finlevcnt(ll crt , ll prv = 0 , ll crp = 0){
for(auto j:adj[crt]){
if(j != prv){
ll o = finlevcnt(j , crt , lc[crt] - lc[j] + crp);
if(o){
return o;
}
}
}
if(adj[crt].size() < 2){
return 0;
}
ll kd = (cnt + 1)/2 >= crp;
for(auto j:adj[crt]){
if(kd == 0){
break;
}
if(j != prv){
if(lc[j] > (cnt + 1)/2){
kd =0;
}
}
}
//std::cout << crt << " " << crp << " " << lc[3] << " " << kd << "\n";
return(kd ?crt :0);
}
ll dfs(ll crt , ll prv){
ll k = 1;
for(auto j:adj[crt]){
if(j != prv){
k = 0;
lc[crt] += dfs(j , crt);
}
}
if(k || adj[crt].size() < 2){
lc[crt] += 1;
cnt++;
}
return lc[crt];
}
void fndlv(ll crt , ll prv){
if(adj[crt].size() < 2){
v.pb(crt);
return;
}
for(auto j:adj[crt]){
if(j != prv){
fndlv(j , crt);
}
}
}
void solve(){
ll n;std::cin >> n;
for(ll i = 0;n-1>i;i++){
ll x , y;std::cin >> x >> y;
adj[x].pb(y);
adj[y].pb(x);
}
dfs(1 , 0);
ll o = finlevcnt(1);
for(auto j:adj[o]){
fndlv(j , o);
}
ll tl = 0;
//std::cout << o << "\n";
ll ps = ((cnt + 1) / 2) * 2;
ll ans [ps];
for(ll i = 0;ps>i;i++){
ans[tl] = v[i % v.size()];
tl+=2;
if(tl == ps){
tl = 1;
}
}
std::cout << ps / 2 << "\n";
for(ll i = 0;ps>i;i+=2){
std::cout << ans[i] << " " << ans[i+1] << "\n";
}
return;/**/
}
signed main(){
std::ios_base::sync_with_stdio(false);std::cin.tie(NULL);
ll t=1;
//std::cin >> t;
ll o = 1;
while(t--){
//cout << "Case " << o++ << ":\n";
solve();
}
return 0;
}/**/
Compilation message
net.cpp:5:78: warning: "/*" within comment [-Wcomment]
5 | #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")/**/
|
net.cpp: In function 'int main()':
net.cpp:114:8: warning: unused variable 'o' [-Wunused-variable]
114 | ll o = 1;
| ^
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
15956 KB |
Output is correct |
2 |
Correct |
9 ms |
15952 KB |
Output is correct |
3 |
Correct |
7 ms |
15956 KB |
Output is correct |
4 |
Correct |
8 ms |
15984 KB |
Output is correct |
5 |
Correct |
8 ms |
15864 KB |
Output is correct |
6 |
Correct |
8 ms |
15956 KB |
Output is correct |
7 |
Correct |
9 ms |
15956 KB |
Output is correct |
8 |
Correct |
8 ms |
15948 KB |
Output is correct |
9 |
Correct |
10 ms |
15956 KB |
Output is correct |
10 |
Correct |
8 ms |
15956 KB |
Output is correct |
11 |
Correct |
8 ms |
15956 KB |
Output is correct |
12 |
Correct |
9 ms |
15956 KB |
Output is correct |
13 |
Correct |
8 ms |
15956 KB |
Output is correct |
14 |
Correct |
7 ms |
15956 KB |
Output is correct |
15 |
Correct |
8 ms |
15956 KB |
Output is correct |
16 |
Correct |
7 ms |
15968 KB |
Output is correct |
17 |
Correct |
8 ms |
15956 KB |
Output is correct |
18 |
Correct |
8 ms |
15956 KB |
Output is correct |
19 |
Correct |
8 ms |
15956 KB |
Output is correct |
20 |
Correct |
10 ms |
15956 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
15956 KB |
Output is correct |
2 |
Correct |
9 ms |
15952 KB |
Output is correct |
3 |
Correct |
7 ms |
15956 KB |
Output is correct |
4 |
Correct |
8 ms |
15984 KB |
Output is correct |
5 |
Correct |
8 ms |
15864 KB |
Output is correct |
6 |
Correct |
8 ms |
15956 KB |
Output is correct |
7 |
Correct |
9 ms |
15956 KB |
Output is correct |
8 |
Correct |
8 ms |
15948 KB |
Output is correct |
9 |
Correct |
10 ms |
15956 KB |
Output is correct |
10 |
Correct |
8 ms |
15956 KB |
Output is correct |
11 |
Correct |
8 ms |
15956 KB |
Output is correct |
12 |
Correct |
9 ms |
15956 KB |
Output is correct |
13 |
Correct |
8 ms |
15956 KB |
Output is correct |
14 |
Correct |
7 ms |
15956 KB |
Output is correct |
15 |
Correct |
8 ms |
15956 KB |
Output is correct |
16 |
Correct |
7 ms |
15968 KB |
Output is correct |
17 |
Correct |
8 ms |
15956 KB |
Output is correct |
18 |
Correct |
8 ms |
15956 KB |
Output is correct |
19 |
Correct |
8 ms |
15956 KB |
Output is correct |
20 |
Correct |
10 ms |
15956 KB |
Output is correct |
21 |
Correct |
8 ms |
15956 KB |
Output is correct |
22 |
Correct |
9 ms |
16048 KB |
Output is correct |
23 |
Correct |
10 ms |
16136 KB |
Output is correct |
24 |
Correct |
9 ms |
16084 KB |
Output is correct |
25 |
Correct |
9 ms |
16084 KB |
Output is correct |
26 |
Correct |
8 ms |
15956 KB |
Output is correct |
27 |
Correct |
9 ms |
16084 KB |
Output is correct |
28 |
Correct |
11 ms |
16084 KB |
Output is correct |
29 |
Correct |
11 ms |
16084 KB |
Output is correct |
30 |
Correct |
9 ms |
15956 KB |
Output is correct |
31 |
Correct |
11 ms |
16048 KB |
Output is correct |
32 |
Correct |
9 ms |
15956 KB |
Output is correct |
33 |
Correct |
8 ms |
15956 KB |
Output is correct |
34 |
Correct |
8 ms |
15956 KB |
Output is correct |
35 |
Correct |
8 ms |
15956 KB |
Output is correct |
36 |
Correct |
7 ms |
15984 KB |
Output is correct |
37 |
Correct |
9 ms |
15956 KB |
Output is correct |
38 |
Correct |
8 ms |
15956 KB |
Output is correct |
39 |
Correct |
9 ms |
15956 KB |
Output is correct |
40 |
Correct |
8 ms |
15932 KB |
Output is correct |
41 |
Correct |
10 ms |
15992 KB |
Output is correct |
42 |
Correct |
10 ms |
15936 KB |
Output is correct |
43 |
Correct |
9 ms |
16016 KB |
Output is correct |
44 |
Correct |
8 ms |
15956 KB |
Output is correct |
45 |
Correct |
9 ms |
15956 KB |
Output is correct |
46 |
Correct |
9 ms |
15992 KB |
Output is correct |
47 |
Correct |
8 ms |
15956 KB |
Output is correct |
48 |
Correct |
8 ms |
15956 KB |
Output is correct |
49 |
Correct |
8 ms |
16020 KB |
Output is correct |
50 |
Correct |
8 ms |
15956 KB |
Output is correct |
51 |
Correct |
8 ms |
15956 KB |
Output is correct |
52 |
Correct |
8 ms |
15956 KB |
Output is correct |
53 |
Correct |
10 ms |
15956 KB |
Output is correct |
54 |
Correct |
10 ms |
15956 KB |
Output is correct |
55 |
Correct |
9 ms |
15992 KB |
Output is correct |
56 |
Correct |
9 ms |
15956 KB |
Output is correct |
57 |
Correct |
8 ms |
15956 KB |
Output is correct |
58 |
Correct |
8 ms |
16084 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
15956 KB |
Output is correct |
2 |
Correct |
9 ms |
15952 KB |
Output is correct |
3 |
Correct |
7 ms |
15956 KB |
Output is correct |
4 |
Correct |
8 ms |
15984 KB |
Output is correct |
5 |
Correct |
8 ms |
15864 KB |
Output is correct |
6 |
Correct |
8 ms |
15956 KB |
Output is correct |
7 |
Correct |
9 ms |
15956 KB |
Output is correct |
8 |
Correct |
8 ms |
15948 KB |
Output is correct |
9 |
Correct |
10 ms |
15956 KB |
Output is correct |
10 |
Correct |
8 ms |
15956 KB |
Output is correct |
11 |
Correct |
8 ms |
15956 KB |
Output is correct |
12 |
Correct |
9 ms |
15956 KB |
Output is correct |
13 |
Correct |
8 ms |
15956 KB |
Output is correct |
14 |
Correct |
7 ms |
15956 KB |
Output is correct |
15 |
Correct |
8 ms |
15956 KB |
Output is correct |
16 |
Correct |
7 ms |
15968 KB |
Output is correct |
17 |
Correct |
8 ms |
15956 KB |
Output is correct |
18 |
Correct |
8 ms |
15956 KB |
Output is correct |
19 |
Correct |
8 ms |
15956 KB |
Output is correct |
20 |
Correct |
10 ms |
15956 KB |
Output is correct |
21 |
Correct |
8 ms |
15956 KB |
Output is correct |
22 |
Correct |
9 ms |
16048 KB |
Output is correct |
23 |
Correct |
10 ms |
16136 KB |
Output is correct |
24 |
Correct |
9 ms |
16084 KB |
Output is correct |
25 |
Correct |
9 ms |
16084 KB |
Output is correct |
26 |
Correct |
8 ms |
15956 KB |
Output is correct |
27 |
Correct |
9 ms |
16084 KB |
Output is correct |
28 |
Correct |
11 ms |
16084 KB |
Output is correct |
29 |
Correct |
11 ms |
16084 KB |
Output is correct |
30 |
Correct |
9 ms |
15956 KB |
Output is correct |
31 |
Correct |
11 ms |
16048 KB |
Output is correct |
32 |
Correct |
9 ms |
15956 KB |
Output is correct |
33 |
Correct |
8 ms |
15956 KB |
Output is correct |
34 |
Correct |
8 ms |
15956 KB |
Output is correct |
35 |
Correct |
8 ms |
15956 KB |
Output is correct |
36 |
Correct |
7 ms |
15984 KB |
Output is correct |
37 |
Correct |
9 ms |
15956 KB |
Output is correct |
38 |
Correct |
8 ms |
15956 KB |
Output is correct |
39 |
Correct |
9 ms |
15956 KB |
Output is correct |
40 |
Correct |
8 ms |
15932 KB |
Output is correct |
41 |
Correct |
10 ms |
15992 KB |
Output is correct |
42 |
Correct |
10 ms |
15936 KB |
Output is correct |
43 |
Correct |
9 ms |
16016 KB |
Output is correct |
44 |
Correct |
8 ms |
15956 KB |
Output is correct |
45 |
Correct |
9 ms |
15956 KB |
Output is correct |
46 |
Correct |
9 ms |
15992 KB |
Output is correct |
47 |
Correct |
8 ms |
15956 KB |
Output is correct |
48 |
Correct |
8 ms |
15956 KB |
Output is correct |
49 |
Correct |
8 ms |
16020 KB |
Output is correct |
50 |
Correct |
8 ms |
15956 KB |
Output is correct |
51 |
Correct |
8 ms |
15956 KB |
Output is correct |
52 |
Correct |
8 ms |
15956 KB |
Output is correct |
53 |
Correct |
10 ms |
15956 KB |
Output is correct |
54 |
Correct |
10 ms |
15956 KB |
Output is correct |
55 |
Correct |
9 ms |
15992 KB |
Output is correct |
56 |
Correct |
9 ms |
15956 KB |
Output is correct |
57 |
Correct |
8 ms |
15956 KB |
Output is correct |
58 |
Correct |
8 ms |
16084 KB |
Output is correct |
59 |
Correct |
402 ms |
45108 KB |
Output is correct |
60 |
Correct |
467 ms |
47720 KB |
Output is correct |
61 |
Correct |
8 ms |
15956 KB |
Output is correct |
62 |
Correct |
10 ms |
15900 KB |
Output is correct |
63 |
Correct |
321 ms |
41936 KB |
Output is correct |
64 |
Correct |
12 ms |
16468 KB |
Output is correct |
65 |
Correct |
17 ms |
18440 KB |
Output is correct |
66 |
Correct |
162 ms |
37052 KB |
Output is correct |
67 |
Correct |
584 ms |
59520 KB |
Output is correct |
68 |
Correct |
584 ms |
58720 KB |
Output is correct |
69 |
Correct |
14 ms |
17100 KB |
Output is correct |
70 |
Correct |
82 ms |
27428 KB |
Output is correct |
71 |
Correct |
294 ms |
51228 KB |
Output is correct |
72 |
Correct |
302 ms |
49768 KB |
Output is correct |
73 |
Correct |
88 ms |
24460 KB |
Output is correct |
74 |
Correct |
480 ms |
44748 KB |
Output is correct |
75 |
Correct |
36 ms |
19884 KB |
Output is correct |
76 |
Correct |
287 ms |
50644 KB |
Output is correct |
77 |
Correct |
279 ms |
51216 KB |
Output is correct |
78 |
Correct |
33 ms |
19984 KB |
Output is correct |
79 |
Correct |
578 ms |
53992 KB |
Output is correct |
80 |
Correct |
9 ms |
16212 KB |
Output is correct |
81 |
Correct |
134 ms |
27368 KB |
Output is correct |
82 |
Correct |
395 ms |
47972 KB |
Output is correct |
83 |
Correct |
501 ms |
44756 KB |
Output is correct |
84 |
Correct |
497 ms |
44864 KB |
Output is correct |
85 |
Correct |
470 ms |
44824 KB |
Output is correct |
86 |
Correct |
470 ms |
47644 KB |
Output is correct |
87 |
Correct |
452 ms |
47688 KB |
Output is correct |